In a typical reinforced concrete residential building, a wall is constructed using a mold made of euro form or plywood. Inner molds are placed spaced apart from each other by a given distance corresponding to a thickness of the wall. Reinforcement bars are installed between the inner molds. An outer mold is coupled to an inner mold. Concrete slurry is poured and cured. Then, the inner and outer molds are removed.
In recent years, consumers are increasingly concerned about the increase in heating energy costs due to rising oil prices. As the government's regulations on insulation design are strengthened due to changes in energy design standards of buildings, inner and outer insulations are separately installed on a wall of a reinforced concrete building.
A reinforced concrete structure is advantageous in structural stability due to high durability, but it is hotter in summer and colder in winter due to its good heat storage property. In order to compensate for this, the external insulation method is employed as a solution to improve insulation while preserving its structural stability. However, there is still a concern of faulty construction due to aging of skilled labors, a shortage of manpower, and a long-rooted in-site practice that construction workers are relying on their own personal experiences rather than following given standard specifications.
In addition, a conventional method of building the concrete wall first and then additionally installing the external heat insulation is disadvantageous in that the process is complicated and an additional construction time is required. On top of that, the in-site practice of relying on individual labors) personal experience rather than following a clear standard may cause issues, for example, a poor adhesive strength due to use of insufficient amount of adhesive, a detachment of an insulation material due to use of a fastener which fails to meet given specifications.
A technique of building a wall in an exterior-insulation-integrated manner is proposed. This technique employs an outer mold and an insulation material is attached to the outer mold.
However, since the concrete wall construction employing the external-insulation integration method is carded out by merely attaching general styrofoam produced in the factory to a mold, cement paste penetrates between heat insulating materials when concrete is poured, causing continuous linear thermal bridge. Metal flat ties are used to connect the molds to each other, to fix the molds, and to keep the molds spaced apart by a given distance. The metal flat ties remain even after the molds are removed, causing continuous point thermal bridges.
A given heat ins dating material has a guaranteed heat transfer rate. However, its actual heat insulation performance may vary depending on what method is used. In particular, a thermal bridge between insulation materials may degrade beat transfer rate of a given heat insulating material. Another issue is it is not easy to procure a proper connection material in the market. To take a full advantage of the guaranteed thermal insulation performance, the thermal bridging between insulation materials should be minimized and a connection material, which connects an insulation material and a wall, must have low thermal conductivity
Recently, an interest in a passive house construction method increases, and many architects wishing to build houses with high insulation performance is increasing. However, due to lack of construction materials and high construction cost, this method is not still popular in the construction market.
Issues related to a conventional heat insulating system will be described below.
Korean Patent No. 0375319 discloses a device shown in FIG. 1. Inner and outer heat insulating plates, in combination, form an integrated block. Therefore, it is convenient to build. Also, it is advantageous in minimizing deformation due to lateral pressure applied when concrete is poured. However, its structural stability is not good and the inner and outer wall connection blocks 3 and 4 takes up a large volume, reducing a space for a concrete wall. In addition, such structure reduces a coating surface. The reduced coating surface increases a risk of corrosion of reinforcement bars. Also, nails (not shown), which are used for fixing the wedges 5 and 6, likely causes a point thermal bridge and an insulation loss. The wedges 5 and 6 connect upper and lower blocks to each other. The block is formed of one body and takes up a large volume. The lame volume makes a carrying cost and a distribution cost expensive.
Korean Patent No. 1027973 discloses a device shown in FIG. 2. Upper and lower panels are connected to each other by engagement holes (not shown) formed in a cross (+) shape. A construction bridge (28) connects the inner panel (11) and the outdoor panel (12) and is made of a bent metal wire. Styrofoam (Neopor) may be used as an insulation panel to obtain a required insulation performance. However, a contact area between the metal wire for connection and the Styrofoam is small. Thus, when concrete is poured, the Styrofoam is easy to be torn out or the metal wire is likely detached by the pressure of the concrete. Furthermore, when the construction bridge (28) is located away a center of the heat insulating panel, a long-term heat loss may occur due to a heat bridge with an outside air.
Korean Patent No. 1079646 discloses a device as shown in FIG. 3. An outer composite panel (100) and an inner composite panel (200) have heat insulating performance and are connected, to each other through a coupling auxiliary key (300) and a coupling ring (400). The inner and outer composite panels (100 and 200) are spaced apart from each other and withstand lateral pressure (horizontal pressure applied to a vertical member of a mold due to fluidity of concrete when the concrete is poured). The size of the metallic coupling protrusion (310) is small compared to the size of the composite panels, and thus the metallic coupling protrusion (310) is likely dislocated due to lateral pressure applied by the concrete. Furthermore, since upper and lower members have no separate recessed grooves, a heat bridge between the members is unavoidable. To avoid this, a caulking (700) has been provided. The caulking (700) is provided to prevent contamination due to leakage of cement paste and prevent cracks between seams, not to bond and insulate the composite panels. Thus, the caulking dislocates and water leaking occurs over time, and thereby beat insulating performance deteriorates.